Pyrometer



C. B. THWING Nov. 5, 1929.

PYROMETER Filed Sept. 5, 1925 Patented Nov'. 5, 1929 UNIT E rATEs CHARLES B. THWING, .OF :PHILADELPHIA PENNSYLVANIA, ASSIGNOB TO THWING INSTRUMENT COMPANY, F PHILADELPHIA, IPENNSYLVANIA, A. CORPORATION OF EENNSYLVANIA '.PYBOMETER Application filed September 8, 1925. Serial No. 54,816. Y Y

My invention relates to pyrometers, and it has particular relation to radiation pyrome ters.

One object of my invention is to provide a radiation pyrometer, of the general character described in my prior Patent No. 919,399, patented April 27, 1909, that shall be characterized by the relatively small angle of view of the pyrometer, permitting readings on very small objects, and by the increased concentration of the radiation at the detector.

Another object of my invention is to provide a device of the class described of compact and rugged design, suitableA for inexpensive quantity production and comprising parts which may be easily made and may be readily `assembled with a minimum expenditure of time and of money.

Other objects and applications of my invention, as well as details of construction and operation, will be apparent more fully hereinafter, when taken in connection with the accompanying drawing,-wherein Fig. 1 is a longitudinal sectional view of a pyrometer embodying my invention;

Fig. 2 is a transverse sectional view illustrating the convex lens, the sectional plane being taken on the line H-I of Fig. 1;

Figs. 3 and 4 are similar views taken on the so lines IIL-H1 and IUT-JV, respectively, of

Fig. 1, but illustrating the detector; and

Fig. 5 is a view similar to Figs. 3 and 4 along the line V-V of Fig. 1, but showing the opposite side of the detector support.

1n the drawings, a pyrometer 1 comprises an elongated tube 2, front and rear sections 3 and 4 of which have adjacent ends 5 and 6 threaded yfor the reception of a coupling sleeve 7 A ring 8 is provided with a threaded .periphery 9 and it is positioned intermediate the adjacent ends 5 and 6.

A front end 11 of the section 3 is threaded for the reception of a cap 12 having an inwardly extending flange 13 adapted to clamp a diaphragm 14, which is provided with a central opening 15, against a .sleeve 16. A pair o rings 17, 17 may be positioned intermedaite the sleeve and the diaphragm 14.

A second diaphragm 8 having a central 50 opening 19 is mounted on a ring 21 adapted to tit within the front tube section 3. The heads of screws 22 and 23, which serve to secure the diaphragm 18 on the ring 21, may abut against the side of the central ring 8. A plurality of additional sleeves 24 are positioned intermediate the sleeve 16 and the supporting ring 21 and are spaced by washers 25 similar to the washer 17. The sleeves 16 and 24 and the washers 17 and 25 and the supporting ring 21, constituting the inner elements of the radiation tube section 3, are coated with a black materia-l. The construction as above defined, permits radiant energy to pass unobstructedly through the apertures 15 and 19 of the diaphragms 14 and 18, respectively, into the concentrating and detector tube section 4.

The section 4 has positioned therein a detector 26 which is'shown in the form of a thermo-electric device, wherein a plurality of thermocouples 27 are connected in series-circuit relation and associated with external circuits (not shown) by means of a pair of conductors 28 and 29. The latter are respectively connected to binding posts 31 and 32 supported on a plate 33 clamped to a rear end 34 of the tube section 4 by means of a threaded cap 35 corresponding to the aforesaid cap 12.

Each thermocouple may comprise a pair of elements 36 and 37, which extend inwardly from supporting posts 38 and 39, respectively, to a common junction point 41. The junction point 41 of the several thermocouples are closely spaced and are positioned at the principal focus of a concave reiector 42 mounted on a threaded adjusting member 43 supported by a plate 44 which also serves to support the posts 38 and 39. The member 44 closely ts within the tube section 4 and it may be spaced from the rear end 34 by means of a sleeve 45.

Radiant energy entering the tube section 4 through the diaphragm 18 may be concentrated upon the thermocouples 27 by means of a member 46 having an inner, highly polished, conical reiiecting surface 47. The member 46 is so mounted on a brass ring 48 that the smaller end of the funnel-shaped reecting surface 47 is in proximity to the thermocouples 27 and the large end is 1n proximity to the diaphragm 18.

The supporting ring 48 may be positioned at the proper distance with respect to the thermocouples 27 by means of a pair of sleeves 49 and A51, the first of which extends between the ring 48 and the central ring 8. The second spacing sleeve 51 is positioned between the ring 48 and the thermocouple supporting plate 44. The spacing sleeves 45, 5l and 49 and the supporting members 8 and 44 are coated with a black substance asis the case with the inner members of the front tube section 3. Thus, the radiant energy entering the tube section 4 is concentrated by the conical reflector surface 47 onY Vthe thermocouples 27 Such radiant energy as passes beyond is reflected back upon said thermocouples by the concave reflector 42.

Another important feature of the present invention is the use of additional means 52 for initially concentrating the radiant energy before it is reflected by the conical reliector 47, which has been shown in the form of a convex lens supported by the intermediate rin 8 directly to the rear of the second diap ragm 18. Practical operation has shown that such construction has many advantages. For example, it makes possible the temperature measurement of smaller objects than has been heretofore possible, and in addition, causes a greater concentration of the radiant energy at the thermocouples 27.v

When the front end 11 of the pyrometer 1 is pointed at a heated body, the radiant energy therefrom passes through thediaphragm openings 15 and 19 and is converged by the convex lens 52 on the conical surface 4 The conical surface 47 causes a complex reflection of the radiant energy, With the result that a maximum concentration occurs at the thermocouples 27. Such energy as passes beyond the thermocouples 27 is reflected backwardly on the same by the concave reiector 42, so that said thermocouples 27 are subjected to amaximum concentration of energy. forces developed by the thermocouples 27 ,establish currents when a galvanometer or other indicating instrument is operatively associated with the binding posts 31 and 32. ile I have shown only one form of embodiment of my invention, for the purpose of describing the same and illustrating its principles of construction and operation, it is apparent that various changes and modifications may be made therein without departingfrom the spirit of my invention, and I' desire, therefore, that only such limitations shall be imposed thereon as are indicated on the appended claims or as are demanded by the prior art.

I claim f 1. A pyrometer comprising a detector, a concave reiiector on one side of said detector,

and a converging lens on the other side thereof.

The resulting electro-motive 2. A pyrometer comprising a detector, means for refiecting the rays passing said detector, means for concentrating the rays on said detector, and means for initially concentrating the rays on said second-mentioned means.

3. A pyrometer comprising a thermocouple, 'a concave reiiector on one side thereof, a funnel-shaped concentrating reflector on the other side thereof, and a converging lens in operative relation to said funnel-shaped reflector. 1

4. A pyrometer comprising a thermocouple, a concave mirror on one side, a concentrating reflector on thebther side, and a lens Yfor converging the rays on said concentrating reiiector. Y

5. A pyrometer comprising a casing having an opening, a diaphragm for said-opening. a detector, a lens positioned intermediate said-detector and said diaphragm. and a concentrating reflector positioned intermediate said lens and said detector.

6. A pvrometer comprising a sectional tube provided with a couplingmember, one sec-A tion of said tube yhaving an opening for ra'- diant energv, the other section containing a detector. a lens positioned within said tube, and a reflector for concentrating the rays phragm in operative relation to said lens',

and a reflector for concentrating the radiant energy passing through said lens on-said detector.

9. A pyrometer comprising a tube having an opening, a diaphragm for said opening adapted to permit radiant energy to enter said tube, a detector positioned Within said tube, a len's positioned intermediate said detector andsaid diaphgram, a second diaphragm in operative relation to said lens, a. reflector for concentrating the radiant energy passing through said lens on 'said detector,

and a second concentrating reiiector adjacent to said detector.

10. A radiation pyrometer comprising a. funnel-'shaped reflector, a lens for converging the desiredradiation on said reflector, heat responsive means operatively associated with the apex of said reiector, and means for preventing the incidence of undesired radiation on the said lens.

l1. In a radiation pyrometer, a funnelfrom theY said opening relatively great with l respect to its distance from the said reflector, whereby the incidence on the lens of substantially all the undesired radiation is prevented.

CHARLES B. THWING. 

